Conventionally, as a damper for a vehicle, for example, as disclosed in JP 2004-239285 A, there has been a damper including: a cylinder; a piston slidably inserted into the cylinder; a piston rod movably inserted into the cylinder and connected to the piston; an extension-side chamber and a compression-side chamber partitioned by the piston in the cylinder; an extension-side port and a compression-side port that are provided in the piston to communicate the extension side chamber with the compression-side chamber; a compression-side leaf valve laminated on the extension-side chamber side of the piston to open and close the compression-side port; an extension-side, leaf valve laminated on the compression-side chamber side of the piston to open and close the extension-side port; and an orifice that communicates the extension-side chamber with the compression-side chamber.
In such a damper, when the piston moves at a low speed with respect to the cylinder, a pressure of the extension-side chamber or the compression-side chamber does not reach a valve opening pressure of the extension-side leaf valve or the compression-side leaf valve, so that hydraulic oil in the cylinder moves between the extension-side chamber and the compression-side chamber via the orifice. Accordingly, as shown in FIG. 9, a characteristic of a damping force (damping force characteristic) of the damper with respect to a piston speed becomes a characteristic peculiar to the orifice, which is proportional to the square of the piston speed when the piston speed is in a low speed range. On the other hand, when the piston speed reaches a high speed range, the extension-side leaf valve or the compression-side leaf valve is opened, and the damping force characteristic of the damper changes to a valve characteristic peculiar to the leaf valve, which is proportional to the piston speed.